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61.
In view of the ongoing discussions concerning the possible designation of the Mediterranean Sea as a Sulphur Emission Control Area (SECA), a modal split model was applied to a case involving the transportation of consolidated cargoes between Thessaloniki, Greece and industrial hubs of northern Germany. A road-only option was assessed against a combined-transport route involving a ferry (Greece–Italy) and a truck-on-train (Italy–Austria) service. The logit model used considers two variables as determinants of the modal selection: transport cost and time. The data are derived from interviews with a small transport service provider, typical for Greece, and are based on actual trips made (revealed preferences). The results predict that the designation of the Mediterranean as a SECA will cause a modal shift in favour of the road-only route by 5.2%, which under certain assumptions can reach 17.1%. However, the environmental implications of the resulting modal choices, calculated through the EcoTransIT World web based tool, are positive in relation to all emissions examined. This is attributed to the longer distance of the combined-transport option in comparison to the road-only one and, the poor environmental performance of the Ro-Pax vessels basically due to the need to maintain a relatively high speed.  相似文献   
62.
结合生产过程中的特殊过程确认与现场控制的一般性要求,围绕着满足摇枕侧架生产制造过程中的一些特殊过程确认与现场控制的细节进行介绍,为指导摇枕侧架生产制造提供理论依据。  相似文献   
63.
An inverse wagon model was developed to estimate wheel–rail contact forces using only measurements of wagon body responses as inputs. The purpose of this work was to provide mathematical modelling to embed in low-cost devices that can be mounted on each freight wagon in a large wagon fleet. To minimize cost, complication, and the maintenance inconvenience of these devices, the constraint is imposed that transducers and connections are limited to locations on the wagon body. Inputs to the inverse model developed include only vertical and lateral translational accelerations and angular accelerations of roll, pitch, and yaw of the wagon body. The model combines the integration and partial modal matrix (PMM) techniques together to form an IPMM method. Besides wheel–rail contact forces some motion quantities such as the lateral and yaw displacements of wheelset are also predicted. Results from the inverse model were compared with data from full scale laboratory suspension tests for vertical suspension excitations. The inverse model was also compared with results from simulations completed in VAMPIRE® for more complicated track input profiles. The model results and the applications of the model are discussed.  相似文献   
64.
刘江茹 《铁道货运》2011,29(7):31-33,50
柳州南站是南宁铁路局路网性贷检站,主要担负着湘桂、黔桂、焦柳线到发列车的贷检工作。柳州南站采用先进的系统集成技术,通过统一的数据接口,利用计算机网络技术、多媒体技术,将柳州南站与贷运安全有关的各个子系统进行整合,做到贷运安全信息与行车实时信息的融合和系统资源共享,形成一套共保贷运安全的监控系统,提高了贷检安全的质量和效率。  相似文献   
65.
“十五”时期,铁路运输工作取得了前所未有的好成绩,铁路旅客周转量、货物发送量、运输密度、总换算周转量等主要指标已稳居世界领先位置。其主要成功经验和做法是:部党组紧紧把握“发展是硬道理”,确立了铁路跨越式发展战略;坚持不懈实施提速战略;始终坚持走挖潜扩能之路;运输管理体制改革和生产力布局调整实现重大突破;全力以赴确保重点物资运输。“十一五”时期,客贷运输新的目标要求是:客运方面,要在高速铁路和既有线再提速、充分发挥客运专线和城际铁路能力、全面提高客运服务质量,以及客运专线的运营管理上取得新突破;贷运方面,要在运输结构调整、推进大客户战略、贷运快捷运输、优化运输组织、深入挖潜提效上取得新突破。  相似文献   
66.
This paper introduces a model of urban freight demand that seeks to estimate tour flows from secondary data sources e.g., traffic counts, to bypass the need for expensive surveys. The model discussed in this paper, referred as Freight Tour Synthesis (FTS), enhances current techniques by incorporating the time-dependent tour-based behavior of freight vehicles, and the decision maker’s (e.g., metropolitan planning agency planner) preferences for different sources of information. The model, based on entropy maximization theory, estimates the most likely set of tour flows, given a set of freight trip generation estimates, a set of traffic counts per time interval, and total freight transportation cost in the network. The type of inputs used allows the assessment of changes in infrastructure, policy and land use. The ability of the model to replicate actual values is assessed using the Denver Region (CO) as a case study.  相似文献   
67.
This paper provides fuel price elasticity estimates for single-unit truck activity, where single-unit trucks are defined as vehicles on a single frame with either (1) at least two axles and six tires; or (2) a gross vehicle weight greater than 10,000 lb. Using data from 1980 to 2012, this paper applies first-difference and error correction models and finds that single-unit truck activity is sensitive to certain macroeconomic and infrastructure factors (gross domestic product, lane miles expansion, and housing construction), but is not sensitive to diesel fuel prices. These results suggest that fuel price elasticities of single unit truck activity are inelastic. These results may be used by policymakers in considering policies that have a direct impact on fuel prices, or policies whose effects may be equivalent to fuel price adjustments.  相似文献   
68.
The paper develops a set of analytical formulations to study the behavior of the urban delivery industry in response to cordon time-of-day pricing, time-distance pricing, and comprehensive financial policies targeting carriers and receivers. This is accomplished by modeling the behavior of receivers in response to financial incentives, and the ensuing behavior of the carrier in response to both pricing and the receivers’ decisions concerning off-hour deliveries. The analytical formulations consider both the base case condition, and a mixed operation with both regular hour and off-hour deliveries; two pricing schemes: cordon time of day, and time-distance pricing; two types of operations: single-tour, and multi-tour carriers; and three different scenarios in terms of profitability of the carrier operation, which include an approximation to the best case, the expected value, and the worst case. The analyses, both theoretical and numerical, highlight the limitations of pricing-only approaches. In the case of cordon time of day pricing, the chief conclusion is that it is of limited use as a freight demand management tool because: (1) in a competitive market the cordon toll cannot be transferred to the receivers as it is a fixed cost and (2) the structure of the cost function, that only provides an incentive to the carrier to switch to the off-hours when all the receivers in the tour switch to the off-hours. The analyses of time-distance pricing clearly indicate that, though its tolls could be transferred to the receivers and provide an incentive for behavior change, the magnitude of the expected toll transfers under real life conditions are too small to have any meaningful impact on receivers choice of delivery times. In essence, the key policy implication is that in order to change the joint behavior of carrier and receivers, financial incentives—or programs that foster unassisted off-hour deliveries—should be made available to receivers in exchange for their commitment to do off-hour deliveries. As the paper proves, if a meaningful number of receivers switch to the off-hours, the carriers are likely to follow suit.  相似文献   
69.
北疆地区地广人稀、自然条件恶劣、风力强劲频繁、降雨量稀少不均匀,存在瞬时洪水及风沙、风蚀、风吹雪等特殊不良地质现象,针对该地区独特的自然环境及地形地质特征,结合红柳河至淖毛湖铁路(货运专线铁路)设计实例,提出铁路站场设计应遵循的原则,根据上述不良地质形成的铁路病害成因及规律,在站址选择、站型、站场路基及车站房屋等方面,提出不同地形地质条件下铁路站场的特殊设计方案。  相似文献   
70.
It is commonly accepted that the modal choice of a shipper is influenced not only by the pure economic attributes of transportation – time and cost – but also by more qualitative factors. These quality attributes relate to frequency, reliability, flexibility, transport duration and risk of loss or damage; they are usually difficult to quantify in monetary terms. Different techniques exist that help to understand better how these different quality attributes of freight transportation influence modal choice. In this paper we apply a stated preference design. Using real business data, the aim is then to derive partial utility functions that allow us to calculate monetary values for these different quality attributes.  相似文献   
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